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8 June 2017

Barcelona blog #6: Nearly Zero Energy Buildings and innovative heating/cooling solutions

Action area 1: Low Energy Districts
To see all the measures to be implemented, click here.

Smart solution 1: Works ongoing in the refurbishment of tertiary building Ca l’Alier

The refurbishment work in the future office building Ca l’Alier is ongoing. The building, owned by a Public-Private Partnership between the Municipality of Barcelona and Cisco, is composed of three units built in 1877 with a total surface of 2,400 m2. It has been out of use for a very long period, and thus suffered from degradation of the building facilities.

The old textile factory will be rebuilt into a nearly Zero Energy Building (nZEB) including a range of passive and active measures. nZEB describes buildings with energy use near to 0 in a “typical year”, meaning that much of the energy consumed comes from the building itself by means of renewable sources. The renovations will be carried out in order to turn the building into a "prototype of a self-sufficient habitat" that produces enough energy resources to meet its own demand. The project aims to achieve a Platinum LEED (Leadership in Energy & Environmental Design) certificate awarded by the US Green Building Council.

Work on the foundation started in June 2016 and finished in April 2017, which is now followed by refurbishments to the basement, paving and underground sewage networks that started in April 2017 and will continue out through 2017.

Foundation work in September 2016. Source: BIMSA

Ongoing refurbishments. Source: BIMSA

Ca l’Alier will demonstrate the feasibility of an nZEB site through active technologies, such as LEDs and occupancy sensors for lighting, variable speed fans and free-cooling for HVAC (Heating, Ventilation and Air Conditioning), photovoltaic panels, connection to the local DHC network that uses waste heat from Municipal Solid Waste incineration, and a Smart Energy Management System. Passive measures include exploitation of natural lighting, wall and roof insulation to lower heating and cooling demands, and rainwater collection to lower water consumption, among others. In order to meet the technical specifications for nZEB, coverage of 70% or more of the consumption of primary energy will be from renewable resources while a special effort in the design has been put on lowering the building energy demand. Also, the energy management system will be capable of optimising current consumption and forecasting the future building energy consumption. Finally, Ca l’Alier will demonstrate the compatibility of open communication protocols with HVAC equipment.

With advanced ICT infrastructure, advanced control of facilities and connection to district energy networks, Ca l’Alier integrates the features of a low energy district and will be an excellent demonstration of smart city solutions in the city of Barcelona.

Smart solution 1: Refurbishment of the Sports Centre

Collaboration Agreement
Following the audit, engineering, proposal and negotiation phases, a participation agreement was reached within GNF and Fundació Claror. The sports centre up for refurbishment within GrowSmarter is the Cartagena Sports Centre, located in the Sagrada Familia neighbourhood in Barcelona.

The refurbishment is taking place under an Energy Services contract, through which the Energy Services Company (ESCo) provides a turnkey solution and provides the initial investment, while the customer pays an annual fee.

Public-Private collaboration
Fundació Claror is a non-profit organisation that manages publicly owned sports centres. The organisation is interested in carrying out energy refurbishments in the facilities they operate to improve sustainability, energy and economic efficiency, and increase comfort.

This and several other sports centres in the city are publicly owned, and exploitation is awarded to private companies by the Barcelona Sports Institute (IBE, in Catalan). This organisation has also participated in negotiations and supported the project.

The Sports Centre
The Cartagena Sports Centre is an urban sports centre with a large swimming pool area (over 600 m2), a spa area, an indoor sports pitch and a fitness area. Other facilities include group activity rooms and spaces dedicated to physical therapy. The total surface area is close to 3,000 m2.

Current equipment mainly consists of natural gas-fired boilers that satisfy most of the heating demand and DHW needs, electric heaters that serve the spa pool, an electric chiller that serves air handling units (AHUs) in the fitness area and other spaces, and dehumidifiers for the pool and spa areas.

Energy Conservation Measures (ECMs)
In the framework of GrowSmarter, an integrated refurbishment of the Centre’s facilities will be carried out, ranging from passive measures that aim to reduce thermal demand to installation of new equipment to increase energy efficiency in the production of thermal energy. The measures selected are intended to complement each other and achieve a technically and economically optimised level of investment and savings. Work in the sports centre began in April 2017.

  • As passive measure, the roof over the main pool hall has been refurbished by adding a layer of insulation within the dropped roof to reduce losses through this surface.

    Initial roof – no insulation

    Insulated roof

  • The heating demand of the pool hall will be further reduced by replacing the current dehumidifier with a new machine that consumes less electricity and includes a thermal recovery module. The bottom line is a reduction of the electricity consumption and heating needs of the pool space, ultimately reducing the amount of heat required from gas-fired boilers.

  • The current chiller will be replaced with a new electric heat pump that produces heating and cooling at a high efficiency. In order to integrate this heat which is available at 40-50ºC, it is necessary to separate existing thermal demands in low temperature and high temperatures through modifications in the distribution system. This solution is especially interesting in buildings with simultaneous heating and cooling needs such as sports centres (pool spaces are often heated while other areas are cooled).

  • To further capitalise on high-efficiency heat from the heat pump, the spa basin will be connected to the new heating ring. This will yield important electricity savings, as it is currently being heated using electric resistance heaters, which are very inefficient.

  • Heating needs not covered by the EHP (e.g. DHW heated up to 70-80ºC for sanitary reasons) will be covered using a new set of high-efficiency boilers replacing the existing ones.

  • Important electricity savings will come from replacing existing lighting equipment with equivalent LED lamps.

  • New equipment and other key systems will be monitored with a new Building Energy Management System (BEMS), which will provide relevant information for more efficient energy management and allow remote monitoring of main energy indicators via web access.

Altogether, total energy consumption is expected to be reduced by more than 40%.

Added value
Gas Natural Fenosa has been offering Energy Services contracts to commercial and industrial customers for several years, including several sports centres in Barcelona, making this project highly replicable in further clients.

Through this contract, Gas Natural Fenosa guarantees energy savings for the sports centre, providing an increased value to the solution from the client’s point of view. Data gathered by the BEMS will be fundamental to assess these energy savings. Furthermore, the company guarantees the correct running of the refurbished systems for the duration of the contract.